Respiratory disease is more common among agricultural workers compared to workers in other industries. However, little attention has been given to workers in the dairy industry. Over the past decade, the dairy industry has changed to rely on more employees. These workers may be exposed at a greater magnitude and duration to agents which cause lung inflammation. The presence of lung inflammation may also be an indicator of asthma, chronic bronchitis, or chronic obstructive pulmonary disease (COPD). Exhaled NO (eNO) has been used extensively as a tool to diagnose asthma and measure the effectiveness of asthma treatments, however eNO has not been used to evaluate lung inflammation among large herd dairy farm workers. Therefore, this study will measure eNO among a sample of large herd dairy farm workers. Occupational exposure to dust and endotoxin will also be assessed among these workers. A generalized linear model will be used to observe relationships between cross shift changes in eNO, and exposure to endotoxin and dust. The proposed research is innovative because there are few studies evaluating relationships between pulmonary health and exposure to agents such as dust and endotoxin among large herd dairy farm workers. The results of this study will have a significant impact on the understanding the relationship between these exposures and pulmonary health among large herd dairy farm workers. This study will provide insight into areas where potential interventions may be developed. PUBLIC HEALTH RELEVANCE: This project will provide information about dust and endotoxin exposures that dairy farm workers experience. This project will also provide information about the relationship of exhaled nitric oxide and pulmonary symptoms to these dust and endotoxin exposures. Learning more about the magnitude, sources and health impact of these exposures will allow for the development of prevention strategies. Finally, the skills acquired by the principal investigator during the course of this study will enable this investigator to perform research independently on future research projects.